dot pitch

The distance between a dot and the closest dot of
the same colour (red, green or blue) on a color CRT. Dot
pitch is typically from 0.28 to 0.51 mm but large presentation
monitors may go up to 1.0 mm. The smaller the dot pitch, the
crisper the image, 0.31 or less provides a sharp image,
especially when displaying text.

Dot pitch measurements between conventional tubes and Sony's
Trinitron tubes are roughly, but not exactly comparable.
Sony's CRTs use vertical stripes, not dots, and its
measurement is the distance between stripes, not the diagonal
distance between dots.